Member Avatar for hassan12345

how to delete line number 3 or any line of my csv file ?????????????????


like
test.csv

1.jhon
2.sarah
3.ricky //delete this row of csv
4.martin

Edited by hassan12345 because: n/a
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  • Latest Post Latest Post by vibhaJ

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For large CSVs, avoid loading the whole file into memory. Text files cannot delete bytes in the middle in-place, so the common pattern is: stream-read the source, write every row except the one you want to remove to a temporary file, then atomically replace the original. This is O(1) memory and scales to hundreds of thousands of lines.

<?php
$source = 'test.csv';
$tmp    = $source . '.tmp';
$skip   = 3; // 1-based line number to remove

$in  = fopen($source, 'rb') or exit('Cannot open source');
$out = fopen($tmp, 'wb')    or exit('Cannot open temp');

// optional locking if other processes may read/write the file
flock($in, LOCK_SH);
flock($out, LOCK_EX);

$line = 0;
while (($row = fgetcsv($in)) !== false) {
    $line++;
    if ($line === $skip) { continue; }
    fputcsv($out, $row);
}

fflush($out);
flock($in, LOCK_UN);
flock($out, LOCK_UN);
fclose($in);
fclose($out);

// replace original (same filesystem for atomic rename)
if (!rename($tmp, $source)) { unlink($tmp); exit('Replace failed'); }

Notes:

  • If the numbers (1., 2., 3.) are part of the data, they will not be auto-renumbered; renumber after the rewrite if needed.
  • fgetcsv handles line endings and quoted fields; do not split on "\n" yourself. See fgetcsv and fputcsv.
  • Use file locks when concurrency is possible: flock.
  • Replace safely with rename; on Windows, ensure no other process holds the file open.

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Member Avatar for Member #120589

Depends, do you want the numbers to follow, or will a simple delete do?

You can:

1. get the contents of the file via file_get_contents().
2. split the contents into an array with explode(), use "\n" as a delimiter.
3. delete the 3rd entry ('2') with array_splice().
4. implode the array using "\n" for the delimiter.
5. save the changes with file_put_contents().

If any of these functions are unfamiliar, look them up in the php.net manual. If stuck, come back, I've got the code, but show your workings first.

Edited by Member #120589 because: n/a
Member Avatar for hassan12345

my csv file is so big it has more than 1 Lac lines.
so i cant offered to delete each line in end of program,,,,i want delete each line after display or process
(display line,then delete this line=>display line,then delete this line..............)

Member Avatar for vibhaJ

Try this.

<?php
$cnt = 0;
if (($handle = fopen("test.csv", "r")) !== FALSE) {
    while (($csvadata = fgetcsv($handle, 0, ",")) !== FALSE) {      
	   $data[$cnt++] = $csvadata;
    }
    fclose($handle);
	unset($data[2]);
}
$fp = fopen('test.csv', 'w');
foreach ($data as $fields) {
    fputcsv($fp, $fields);
}
fclose($fp);
?>
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